118 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. * 



Sepals very acute, pale green or straw-colored, equaling or exceeding the pale 

 capsule; leaves all basal or essentially so. 

 Leaves sub terete, merely channeled above; basal sheaths usually purplish- 

 tinged; flowers 3.5-5 mm. long, in 1-sided racemes; leaf sheaths with 

 short cartilaginous auricles (the narrow borders at the apex of the 



sheaths) 7. J. dichotomus. 



Leaves flattened, but sometimes inrolled in drying so as to appear involute; 

 basal sheaths brownish or straw-colored. 

 Auricles of the leaf sheaths cartilaginous, yellowish when dry. 



4. J. dudleyi. 



Auricles of the leaf sheaths membranaceous or submembranaceous, 



whitish or brownish. 



Auricles thin, scarious, whitish, 1-3 mm. long; flowers 3.5-5 mm. 



long, loosely scattered or clustered; inflorescence shorter than its 



lowest bract 5. J. tenuis. 



Auricles firmer, brownish, less than 1 mm. long; flowers 2.5-3.5 mm. 

 long, arranged in 1-sided racemes; inflorescence usually longer than 

 its lowest bract 6. J. secundus. 



1. Juncus effusus L. Common rush. 

 Meadows and wet places; rather common. June-Aug. N. Amer..and Eur. 



The form occurring with us is J. effusus solutus Fern. & Wieg. 



2. Juncus bufonius L. Toad rush. 

 Dried-up pools and wet places; common. May-July. Cosmopolitan. 



3. Juncus gerardi Loisel. Black grass. 

 Known only from streets of Alexandria,where first collected by Vasey . July. Nearly 



cosmopolitan. 

 Abundant, outside our limits, in the salt marshes of Chesapeake Bay. 



4. Juncus dudleyi Wiegand. 



Sandy bogs and damp sands; scarce; flats of the Potomac, southwest of Washington 

 Monument (CoriZZe); High Island and First Lock (PFarrf). May-June. Greater part of 

 N. Amer. 



5. Juncus tenuis Willd. Path rush. 

 Abundant throughout in sandy soil; a characteristic plant along paths. June- 

 Aug. N. Amer.; introd. and spreading in the Old World. 



6. Juncus secundus Beauv. 



Fairly common in sandy abandoned fields. June. Eastern N. Amer. (/. tenuis 

 secundus Engelm.) 



7. Juncus dichotomus Ell. 



Low sandy ground and meadows; frequent, especially toward salt water. June- 

 Sept. Eastern N. Amer.; trop. Amer. 



8. Juncus marginatus Rostk. 



Meadows and wet grounds; abundant. June-Sept. Eastern N. Amer. (Includes 

 J. marginatus vulgaris of Ward's Flora.) 



9. Juncus aristulatus Michx. 



Frequent in grassy places. June-July. Eastern N. Amer., south to Mex. (J. 

 marginatus hiflorus of Ward's Flora; /. marginatus aristulatus Coville.) 



10. Juncus torreyi Coville. 



Damp sandy ground; scarce; vicinity of Washington {Ward); reservoir, Howard 

 University, and Jackson City (Steele). July-Aug. Eastern N. Amer. (/. nodosus 

 megacephalus Engelm.) 



11. Juncus scirpoides Lam. 



Wet sandy soil; common. July-Aug. Eastern N. Amer. (/. scirpoides macroste- 

 mon Engelm.) 



